<template>
  <div>
    我是num组件----{{ abc }}---- <button @click="setAbc">修改abc</button>
  </div>
</template>
<script>
export default {
  props: {
    abc: { type: Number, required: true }
  },
  methods: {
    setAbc() {
      this.$emit('update:abc', Math.random() * 999)
    }
  }
}
</script>
<style></style>
